diabetic neuropathy

Diabetic Neuropathy

Definition

Diabetic neuropathy is a nerve disorder caused by diabetes mellitus. Diabetic neuropathy may be diffuse, affecting several parts of the body, or focal, affecting a specific nerve and part of the body.

Description

The nervous system consists of two major divisions: the central nervous systems (CNS) which includes the brain, the cranial nerves, and the spinal cord, and the peripheral nervous system (PNS) which includes the nerves that link the CNS with the sensory organs, muscles, blood vessels, and glands of the body. These peripheral nerves are either motor, meaning that they are involved in motor activity such as walking, or sensory, meaning that they carry sensory information back to the CNS. The PNS also works with the CNS to regulate involuntary (autonomic) processes such as breathing, heartbeat, blood pressure, etc.

There are two types of diffuse diabetic neuropathy that affect different nervous system functions. Diffuse peripheral neuropathy primarily affects the limbs, damaging the nerves of the feet and hands. Autonomic neuropathy is the other form of diffuse neuropathy and it affects the heart and other internal organs.

Diabetic neuropathy can lead to muscular weakness, loss of feeling or sensation, and loss of autonomic functions such as digestion, erection, bladder control, and sweating among others.

The longer a person has diabetes, the more likely the development of one or more forms of neuropathy. Approximately 60-70% of patients with diabetes have neuropathy, but only about 5% will experience painful symptoms.

Causes and symptoms

The exact cause of diabetic neuropathy is not known. Researchers believe that the process of nerve damage is related to high glucose concentrations in the blood that could cause chemical changes in nerves, disrupting their ability to effectively send messages. High blood glucose is also known to damage the blood vessels that carry oxygen and other nutrients to the nerves. In addition, some people may have a genetic predisposition to develop neuropathy.

There is a wide range of symptoms associated with diabetic neuropathy, and they depend on which nerves and parts of the body are affected and also on the type of neuropathy present. Some patients have very mild symptoms, while others are severely disabled.

In severe diabetic neuropathy loss of sensation can lead to injuries that are unnoticed, progressing to infections, ulceration and possibly amputation.

Diagnosis

The diagnosis of neuropathy is based on the symptoms that present during a physical exam. Pain assessment is usually the first step. Patients may have more than one type of pain, and the history helps the doctor determine whether a the pain has a neuropathic cause.

The exam may include:

a screening test for lost sensation

nerve conduction studies to check the flow of electric current through a nerve

electromyography (EMG) to see how well muscles respond to electrical impulses transmitted by nearby nerves.

ultrasound to show how the bladder and other parts of the urinary tract are functioning

sometimes a nerve biopsy may be performed.

Specialists who treat diabetic neuropathy include:

neurologists: specialists in nervous system disorders

urologists: specialists in urinary tract disorder

gastroenterologists: specialists in digestive disorders

podiatrists: specialists in caring for the feet

Treatment

Treatment of diabetic neuropathy is usually focused on treating the symptoms associated with the neuropathy and addressing the underlying cause by improving the control of blood sugar levels, which may heal the early stages of neuropathy.

There is no cure for the permanent nerve damage caused by neuropathy. To help control pain, the choice of proven drug therapies has broadened during the past decade. Pain medication, such as the topical skin cream capsaicin, is usually no stronger than codeine because of the potential for addiction with long-term use of such drugs. Four main classes of drugs are available for pain management, alone or in combination: tricyclic antidepressants (Imipramine, Nortriptyline), narcotic analgesics (Morphine), anticonvulsants (Carbamazepine, Gabapentin), and antiarrhythmics.

Key terms

Central nervous system (CNS) — Part of the nervous system consisting of the brain, cranial nerves, and spinal cord. The brain is the center of higher processes, such as thought and emotion, and is responsible for the coordination and control of bodily activities and the interpretation of information from the senses. The cranial nerves and spinal cord link the brain to the peripheral nervous system.

Diabetes mellitus — Disease characterized by the inability of the body to produce or respond properly to insulin, required by the body to convert glucose to energy.

Peripheral nervous system (PNS) — One of the two major divisions of the nervous system. PNS nerves link the central nervous system with sensory organs, muscles, blood vessels, and glands.

Prognosis

Early stage diabetic neuropathy can usually be reversed with good glucose control. Once nerve damage has occurred it cannot be reversed. The prognosis is largely dependent on the management of the underlying condition, diabetes, which may halt the progression of the neuropathy and improve symptoms. Recovery, if it occurs, is slow.

Prevention

Tight glucose control and the avoidance of alcohol and cigarettes help protect nerves from damage.

neuropathy

[noo͡-rop´ah-the]

any of numerous functional disturbances and pathologic changes in the peripheral nervous system. The etiology may be known (e.g., arsenical, diabetic, ischemic, or traumatic neuropathy) or unknown. encephalopathy and myelopathy are corresponding terms relating to involvement of the brain and spinal cord. The term is also used to designate noninflammatory lesions in the peripheral nervous system, in contrast to inflammatory lesions (neuritis). adj., adj neuropath´ic.

alcoholic neuropathy neuropathy due to thiamine deficiency in chronic alcoholism.

diabetic neuropathy a complication of diabetes mellitus consisting of chronic symmetrical sensory polyneuropathy affecting first the nerves of the lower limbs and often affecting autonomic nerves. Pathologically, there is segmental demyelination of the peripheral nerves. An uncommon, acute form is marked by severe pain, weakness, and wasting of proximal and distal muscles, peripheral sensory impairment, and loss of tendon reflexes. With autonomic involvement there may be orthostatic hypotension, nocturnal diarrhea, retention of urine, impotence, and small diameter of the pupils with sluggish reaction to light.

entrapment neuropathy any of a group of neuropathies, such as carpal tunnel syndrome, caused by mechanical pressure on a peripheral nerve.

hereditary motor and sensory neuropathy (HMSN) any of a group of hereditary polyneuropathies involving muscle weakness, atrophy, sensory deficits, and vasomotor changes in the lower limbs. Some diseases in this group have been numbered: types I and II are varieties of Charcot-Marie-Tooth disease and type III is progressive hypertrophic neuropathy.

hereditary sensory and autonomic neuropathy (HSAN) any of several inherited neuropathies that involve slow ascendance of lesions of the sensory nerves, resulting in pain, distal trophic ulcers, and a variety of autonomic disturbances. Types include hereditary sensory radicular neuropathy and familial dysautonomia.

Leber's optic neuropathy a maternally transmitted disorder characterized by bilateral progressive optic atrophy, with onset usually at about the age of twenty. Degeneration of the optic nerve and papillomacular bundle results in progressive loss of central vision that may remit spontaneously. It is much more common in males. Called also Leber's disease and Leber's optic atrophy.

progressive hypertrophic neuropathy a slowly progressive familial disease beginning in early life, marked by hyperplasia of interstitial connective tissue, causing thickening of peripheral nerve trunks and posterior roots, and by sclerosis of the posterior columns of the spinal cord, with atrophy of distal parts of the legs and diminution of tendon reflexes and sensation. Called also Dejerine's disease and Dejerine-Sottas disease.

serum neuropathy a neurologic disorder, usually involving the cervical nerves or brachial plexus, occurring two to eight days after the injection of foreign protein, as in immunization or serotherapy for tetanus, diphtheria, or scarlet fever, and characterized by local pain followed by sensory disturbances and paralysis. Called also serum neuritis.

di·a·bet·ic neu·rop·a·thy

a generic term for any diabetes mellitus (DM)-related disorder of the peripheral nervous system, autonomic nervous system, and some cranial nerves.

This most common of the chronic complications of DM can affect the peripheral or the autonomic nervous system, singly or in combination. Peripheral neuropathies can cause bilaterally symmetric hypesthesia, hyperesthesia, paresthesia, loss of temperature and vibratory sense, or causalgia. With more advanced disease, deep tendon reflexes and proprioception may be impaired. Peripheral mononeuropathies (Bell palsy, radiculopathy) can mimic neurologic diseases of other origin. Sensory neuropathy is believed to play a role in at least half of all lower limb amputations in patients with DM by blunting awareness of cutaneous injuries, which then fail to heal because of macrovascular circulatory impairment. Sensory neuropathy to a degree that can lead to ulceration or gangrene can be detected by examination of the foot with a 10-g monofilament. Involvement of the autonomic nervous system may be manifested by postural hypotension, dysphagia, gastroparesis, alternating diarrhea and constipation, and impotence. The pathogenesis of chronic diabetic neuropathy is poorly understood. Symptoms tend to progress and the response to treatment is unpredictable. In contrast, cranial nerve palsies due to microangiopathy in DM often resolve spontaneously.

diabetic neuropathy

n.

Peripheral neuropathy occurring as a complication of untreated or improperly controlled diabetes mellitus.

diabetic neuropathy

a noninflammatory disease process associated with diabetes mellitus and characterized by sensory and/or motor disturbances in the peripheral nervous system. Patients commonly experience degeneration of sensory nerves and pathways. Early symptoms, which include pain and loss of reflexes in the legs, may occur in patients with only mild hyperglycemia. Diabetes is associated with a wide range of neuropathies, including mononeuritis multiplex, compression and entrapment mononeuropathies, cranial neuropathies, and autonomic and small fiber neuropathies. Differential diagnosis is difficult because not all sensorimotor neuropathies are caused by diabetes.

di·a·bet·ic neu·rop·a·thy

(dī-ă-bet'ik nūr-op'ă-thē)

A generic term for any diabetes mellitus-related disorder of the peripheral nervous system, autonomic nervous system, and some cranial nerves. This most commonly occurring of the chronic complications of diabetes takes two forms, peripheral (with dulling of the sensations of pain, temperature, and pressure, especially in the lower legs and feet), and autonomic (with alternating bouts of diarrhea and constipation, impotence, and reduced cardiac function).

NEUROPATHIC FOOT DUE TO DIABETES

diabetic neuropathy

Damage to autonomic, motor, and/or sensory nerves due to metabolic or vascular derangements in patients with long-standing diabetes mellitus. In Western nations, diabetes is the most common cause of neuropathy. Symptoms usually include loss of sensation or unpleasant sensations in the feet, erectile dysfunction, focal motor deficits, gastroparesis, loss of the ability to maintain postural blood pressure, and diseases of cardiac innervation. Sensory loss in the feet may result in undetected injuries that become infected or gangrenous. Synonym: diabetic polyneuropathy See: illustration

Treatment

Tight control of blood sugar levels may prevent some neuropathic symptoms in patients with diabetes mellitus.

di·a·bet·ic neu·rop·a·thy

(dī-ă-bet'ik nūr-op'ă-thē)

Generic term for any diabetes mellitus-related disorder of the peripheral nervous system, autonomic nervous system, and particular cranial nerves.

neuropathy

a general term denoting functional disturbances and pathological changes in the peripheral nervous system. The etiology may be known (e.g. poidoning by arsenicals, ischemic or traumatic neuropathy) or unknown. Encephalopathy and myelopathy are corresponding terms relating to involvement of the brain and spinal cord, respectively. The term is also used to designate noninflammatory lesions in the peripheral nervous system, in contrast to inflammatory lesions (neuritis).

a chronic symmetrical sensory polyneuropathy associated with diabetes mellitus in humans, which occurs uncommonly in dogs and cats.

entrapment neuropathy

a neuropathy due to mechanical pressure on a peripheral nerve.

giant axonal neuropathy

a familial disease of German shepherd dogs, characterized by ataxia, hypotonia, reduced pain sensation, and loss of reflexes and proprioception in the hindlegs, which develops from a young age. Vomiting, associated with esophageal dilatation, also occurs.

hereditary neuropathy

recorded in Tibetan mastiff as an inherited defect in myelin production. Weakness, loss of reflexes and quadriplegia develop quickly and at an early age.

hereditary sensory neuropathy

an inherited abnormality in which affected dogs have impaired perception of pain in the feet and lower limbs from a young age; causes extensive self-mutilation of toes and footpads. It occurs in German shorthaired pointers, English pointers and English springer spaniels. Called also acral mutilation syndrome.

Patient discussion about diabetic neuropathy

Q. My blood sugars are usually in the range of 180 (when I first get up) to about 240 in evening.. normal? I have been told I have Diabetes Type II.
one doctor put me on metformin.. then that doc retired. Next doc said I don't need metformin. But I have noticed by checking blood sugars at home, they seem a little high. Also have been having some sweating, headaches, and some pain in feet and weird burning in feet.. Is that from high blood sugar?
What is high? Should I tell my doc what my readings are?
Do you think I need to get on a medication? I am trying diet modification and some exercise (I have a bad back and can't do much exercise or walking)... just don't want to get damage to my body from high blood sugars. thanks

A. Your readings does describe diabetes, and metformin is considered as the first line treatment for diabetes, however, giving diet and exercise a chance before starting meds was considered a legitimate approach before. I think that informing your doctor is a very good idea. The complaints your describe may result from diabetes, although not necessarily.

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